Soft Partition:
1TB total space available in storage in all mapped to the OS to be configured to each partition so that each partition of the file system is set by the OS (control and manage partitions is done by the OS)

Hard Partition:
1TB total space available in storage is divided into multiple partitions to be configured for each file system in the OS, the division is done at the level of storage, so as not to burden the performance of the OS (control and managed by storage).

Which one the best configuration for solaris system? On this storage running SAP system.

You can think of soft partitioning as a logical partition. It's a feature of the volume manager that Solaris provides. A hard partition will usually be "faster", but a lot depends on how you have things configured to begin with.

Soft partitions, because they are more abstract can be viewed as "friendlier" or "more flexible".

IMHO, if performance is a must, then you're likely going to be going SSD, etc...

So personally, I prefer the flexibility that soft partitioning provides. Obviously things that are wanting a true partition (some enterprise software may require it) you'll have no choice.

There's a chicken and egg problem with things under Solaris volume management, so there are still places like early on in the boot where hard partitions are going to be required. Depending on the complexity of your storage, it may also have that kind of requirement. But, after boot, if all visible as disk... I say pool it up and carve it up logically.